Chairs



May 12, 1970 P. 'ACKERMANN CHAIRS 2 Sheets-Sheet 1 Filed April 17, 1968 FIGS x w W INVENTOR WILI-IELM PAUL ACKERMANN u 20o. 20b BY FIG IO ATTORNEYS May 12, 1970 F L K 3,511,537

CHAIRS 2 Sheets-Sheet 2 Filed April 17, 1968 ii? in,

INVENTOR WIYLHELM PAUL ACKER MANN ATTORNEYS United States Patent 3,511,537 CHAIRS Wilhelm Paul Ackermann, 50 Sturegatan, 114 Stockholm 36, Sweden Filed Apr. 17, 1968, Ser. No. 721,960 Claims priority, application Sweden, Mar. 25, 1963, 3,219/ 63 Int. Cl. A47c 7/24 US. Cl. 297-454 3 Claims ABSTRACT OF THE DISCLOSURE A chair having a seat surface and a back support surface. The seat surface has an elevated front portion and a lower rear portion with the transition line between the front portion and the rear portion forming a well defined edge extending from one side to the other across the seat surface and being located at a distance from the transition line between the seat surface and the back support surface. Such distance should be sufiicient for the ischiums of a sitting person to be supported in a vertical direction by the rear portion of the seat surface and at the same time supported in a horizontal direction by such edge to prevent a seated person from sliding forwardly on the seat surface. The lower rear portion of the seat surface is of harder material than the elevated front portion.

This application is a continuation-in-part of my application Ser. No. 568,237 filed July 27, 1966 entitled Chairs, which was a continuation-in-part of my application Ser. No. 354,041 filed Mar. 23, 1964 entitled Chairs, both now abandoned.

An object of the present invention is to provide a support for the ischiums and the sacrum of a sitting person to avoid displacements of such organs.

1 A further object is to provide an insert which may be placed in a chair or an automobile seat.

A further object is to provide support means having a well defined rear edge so as to support a sitting person in both a horizontal and a vertical position.

A still further object is to provide support means for maintaining the ischiums of a sitting person in parallel relationship.

With the above and other objects in view which will become apparent from the detailed description below, some preferred embodiments of the invention are shown in the drawings in which:

FIG. 1 is a diagrammatic view of an easy chair of an ordinary type and a part of the skeleton of a person sit ting in the chair, all being shown in a side view;

FIG. 2 is a view of the same chair as in FIG. 1 with a support means according to the invention, similarly in side view;

FIG. 3 is a diagrammatic view from the rear showing how an inclined seat surface affects the skeleton of a sitting person;

FIG. 4 is a side view of the skeleton portion as shown in FIG. 3;

FIG. 5 shows the same skeletonportion as in FIG. 3 when placed on a straight and rigid seat surface according to the invention;

FIG. 6 is a side view of the skeleton portion as shown in FIG. 5;

FIG. 7 is a diagrammatic side view of an insert member according to the invention, designed to be used with an easy chair;

FIG. 8 is a frontal perspective view of the device as shown in FIG. 7;

FIG. 9 illustrates a section of the device as shown in FIG. 8, taken along the line IX-]X and being seen in 3,511,537 Patented May 12, 1970 the direction of the arrows, showing one embodiment of the invention;

FIG. 10 similarly illustrates one embodiment of the invention in section along the line XX in FIG. 8 and seen in the direction of the arrows;

FIG. 11 is a sectional view of another embodiment of the invention.

In FIG. 1 there is shown the seat surface 1 and the back surface 2 of the usual easy chair or car seat. The spinal column 3 of the sitting person has at the lowermost end thereof the sacrum 4 disposed between the halves of the pelvis portion 5. As is obvious in a chair of this general type the sitting person does not achieve an anatomically correct support.

The arrow 6 indicating the lowermost portion of the spinal column 3 tends to be displaced rearwardly into the soft upholstery of the back support. Also, simultaneously the pelvis 5 tends to slide forwardly in the direction of the arrow 7, which contributes even more to the tendency of the lowermost portion of the spinal column to be displaced rearwardly. Furthermore, the ischiums of the pelvis portion 5 sinks down into the soft upholstery of the seat surface 1, as is shown by the arrow 8.

In FIG. 3 it is indicated that this lowering may be nonsymmetric, viz. one side 9 of the pelvis portion 5 may lower itself to a greater extent than the other side 10. The sacrum 4 will be turned with the result that the lowermost portion of the spinal column 3 assumes an inclined position as shown. This bend of the spinal column is accompanied by an opposite bend slightly higher up and the spinal column assumes an S-shape.

This non-symmetry causes one of the pelvis halves to be turned forwardly to a greater extent than the other one, as shown in FIG. 4. By extended or repeated sitting on chairs which give such a support it may happen that such a displacement becomes permanent to a greater or lesser extent and cause a person to walk with a slight hitch in his gait. Naturally, also other troubles arise, such as ache, tiredness and so on.

The non-symmetry of the supporting properties of an easy chair or a plain chair of the common type is particularly present in automobile seats. Due to the camber of the road surface the seat surface of an automobile seat slopes to the left in countries with left hand traffic and to the right in countries with right hand traffic. Thi initial slope results in a basic non-symmetrical support. In use this non-symmetry is aggravated in as much as the initial- 1y lowermost point due to that inclined position of the sitting person which the non-symmetry gives rise to, results in the pressure at this point being higher than at the point initially higher up.

Contributing to the non-symmetrical support troubles in particular with automobile seats are also the impacts and vibrations occurring during travel. These movements cause correpsonding compressions of the upholstery of the seat surfaces, for which reason the deformation takes place at a faster rate than is the case with the usual chairs.

One circumstance which contributes to a sitting person not being afforded a satisfying support in car seats of the conventional type, is also that the seat surface moves resiliently in the vertical direction with respect to the vertically stationary back surface. In FIG. 1 it has been shown that certain points of the spinal column, such as indicated by the arrows 6 and 11, respectively, are pressed heavily against the back surface 2. As the seat surface 1 makes a movement vertically the back of the sitting person will slide correspondingly upwardly and downwardly along the back surface of the chair. By this movement a considerable heat development occurs at the points which are heavily pressed against the back surface, which is very undesirable from many points of view. Among other things the degenerative effect on the intervertebral disks which the already deformed spinal column brings about will be even more aggravated. Furthermore, the overstressing of the back muscles which is due to the bad supporting properties of the seat means will be aggravated.

In the chair of the present invention, illustrated in FIG. 2, there is provided a vertically adjustable protrusion 12 which gives a support to the pelvis 5, the sacrum 4 and the spinal column 3 so that stresses at the connection of the sacrum to the pelvis are avoided. By adjusting the protrusion 12 vertically the position thereof may be adapted to the person who uses the seat most frequently.

The seat in FIG. 2 has a horizontally adjustable protrusion 13 on the seat surface thereof. Such protrusion affords a support in the horizontal direction for both ischiums of the pelvis portion to prevent these from sliding forwardly on the seat surface by a force as indicated by the arrow 14. Therefore, the support points for the ischiums in the vertical direction, as set forth by the arrow 15, will remain in such a position that the sacrum 4 maintains its anatomically correct position in relation to the pelvis.

Furthermore, in a seat means according to the invention, those surfaces which afford a support in the vertical direction to the ischiums and afford a support in the horizontal direction to the spinal column and the sacrum (at the arrow 16) have to be rigid. They should be constituted by non-resilient panels, provided with only a thin upholstery (1 to 2 centimeters thickness).

The rear part of the seat surface should be unyielding and sufficiently hard to keep the ischiums at the same horizontal level.

Furthermore, the vertical surface should be adjustable to a correct horizontal position.

By the invention, both ischiums of the pelvis are afforded a correct support, so that the spinal column is not subjected to abnormal bendings or other deformations. FIGS. 5 and 6 illustrate the correct mutual position between the pelvis 5, the sacrum 4 and the spinal column 3 which will be obtained in this case.

To prevent the seat surface from vertical movements relatively to the back surface it is preferred to connect the rearmost edge of the seat surface to the lowermost edge of the back surface by means of a hinge or in an other non-flexible manner, so that the distance of the seat surface from the support points (e.g. the protrusion 12) of the back surface is always maintained constant.

A very advantageous embodiment of the invention is in the shape of an insert, arranged to be placed in a chair or easy chair of a conventional type, such as in an automobile seat.

The insert means comprises a panel 20 of hard board, for instance, which panel affords a seat surface. On the uppermost side the panel 20 is provided with a comparatively thin upholstery 21. Further, the insert means comprises a back surface panel 22, similarly of hard board or another suitable material, which constitutes a back support surface. Also this panel 22 is provided with a comparatively thin upholstery 23. The lowermost edge of the back support panel 22 and the rearmost edge of the seat panel 20 are connected to each other by means of one or more hinges 24 or the like, which affords a possibility to fold the insert so as to make it easy to transport. Also, the angle between the panels will automatical- 1y adjust itself to the chair into which the insert is placed.

The panel 20 has a horizontally adjustable protrusion 25. This protrusion is preferably constituted by a panel 26 with a comparatively rigid upholstery 27 placed thereon. The protrusion is secured to the panel 20 simply since it is provided with one or more resilient bands 28, which embrace the panel 20. This also makes the protrusion 25 easily slidable horizontally on the panel 20. The protrusion 25 is designed to afford a correct support in the horizontal direction to the ischiums. To

this end it has a well defined rear edge 29, whereas for the remaining portion thereof it has a slight inclination forwardly.

correspondingly, the back support panel 22 is provided with a protrusion 30. Also this protrusion consists of a panel 31, carrying a comparatively rigid upholstery 32. The protrusion 30 is secured to the panel 22 by means of two resilient bands 33 and 34 so that the protrusion is vertically slidable on the panel 22. The protrusion 32 is designed to afford a correct support to the pelvis, the sacrum and the spinal column. To this end it has, as seen from below, first a lower portion 35 to support the uppermost portion of the pelvis and the sacrum, then a bead 36 to support the lowermost portion of the spinal column, and finally a lower portion 37 to afford a correct support to the middle portion of the spinal column.

In FIG. 8 the insert in FIG. 7 is illustrated i a frontal perspective view.

The insert in FIGS. 7 and 8 is very easy to remove from the seat (such as a car seat) in which it is used. Due to the possibility of folding out the insert around the hinges 24 so as to form a flat, hard panel, and in view of the fact that the protrusions 23 and 30 may easily be removed from the same the insert may be used as a sup-port in the bed of such persons that want to have a hard supporting base due to back complaints, for instance.

In FIG. '9 the back support .panel of the invention is shown in section. In this embodiment the back support panel is divided up into three portions along vertical lines. The two outermost portions 22a and 22b are stiff and consist of hard board or the like. The middle portion 220 is soft and flexible, and this portion is preferably made of a textile material. In this embodiment the adjustable protrusion 30 is preferably provided with a soft bottom panel, which forms itself to the different positions which the portions 22a, 22b and 22c, respectively, may assume in relation to each other. The device as shown in FIG. 9 is well adapted for use in a car seat in as much as it affords a better contact between the insert and the seat means of the car.

FIG. 10 shows in section a preferred embodiment of the seat surface of an insert for automobile seats. In this case only the rearmost portion 20a of the seat panel is made of a rigid material. The front portion 20b is made of a resilient material, such as textile material. The front portion 20b carries the protrusion 25. From a practical point of view the protrusion in this case may be nonadjustably secured to the seat surface, and it may be made of a comparatively rigid but resilient upholstery. A seat surface of this kind affords a better contact with the seat means of the automobile, which is an advantage in driving.

In the use of an insert according to FIGS. 7 and 8 it is possible to adjust the horizontal position of the seat surface by placing an interleaf of any desired kind, such as a folded piece of clothing, a pad of sponge rubber or the like, between the seat panel 20 and the seat surface of the chair and on the side, to which the seat panel is inclined. Also it is possible to introduce such interleaves under the adjustable protrusion 25, which is possible in view of the fact that the band 28 is resilient.

In a corresponding manner it is also possible to adjust the back support surface 22 to the correct angular position, should this 'be found necessary.

In the embodiment in FIG. 11 a panel 40 of a hard material is placed within the seat surface. Over the panel 40 there is disposed a comparatively thin upholstery 41. This upholstery extends forwardly and has a well defined edge which forms the support means according to the invention. Above the upholstery 41 there is disposed a very soft upholstery 43 the uppermost surface of which is situated in the same plane as that of the foremost portion 45 of the seat surface upholstery. In this embodiment the support means 42 according to the invention is invisible when the chair is not being used, but still it is just as efiicient as in the above discussed embodiments.

I claim:

1. In a seat construction, the combination of a seat surface and a back support surface, said seat surface having an elevated front portion and a lower rear portion, the transition line between said front portion and said rear portion forming a well defined edge, said edge being parallel to said transition line and extending from one side to the other across said seat surface and being located at a distance from the transition line between said seat surface and said back support surface which is sufficient for the ischiums of a person using the seat construction a normal way to be supported in a vertical direction 'by said rear part of said seat surface when the upper part of the pelvis is supported in a horizontal direction by said back support surface, said ischiums being supported in a horizontal direction by said edge for preventing the seated person from sliding forwardly on said seat surface, said lower, rear portion of said seat surface being plane, even and unyielding, and being of sufficiently hard material to keep the ischiums substantially on the same horizontal level.

2. In a seat construction according to claim 1, a soft upholstering covering said rear portion of said seat surface, the upper surface of said soft upholstering being on the same level as the upper surface of the front part of the seat surface, said upholstering being sufiiciently soft so that said upholstering allows the ischiums of a seated person a firm support in the vertical direction by said rear part of said seat surface.

3. A chair comprising a seat surface having an elevated front portion and a lower rear portion and a back support surface connected to said seat surface, an edge between said elevated front portion and said lower rear portion extending from one side to the other transversely across said seat surface spaced from a line connecting said seat surface and said back support surface for supporting the ischiums of a person normally using the chair in a vertical direction by said rear portion when the upper part of the pelvis of such person is supported in a horizontal direction by said back support surface, said ischiums being supported in a horizontal direction by said edge for preventing a seated person from sliding forwardly on said seat surface and said lower, rear portion being plane, even and unyielding, and being of a hard material to keep said ischiums substantially on the same horizontal level.

References Cited UNITED STATES PATENTS 2,833,340 5/1958 Shapiro {297458 2,836,226 5/1958 Fridolph 297458 3,177,036 4/1965 Halter 297459 3,193,328 7/1965 Baermann 297456 CASMIR A. NUNBERG, Primary Examiner US. Cl. X.R. 

